1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing a carbon fiber woven fabric using a water-jet loom.
2. Description of the Prior Art
Carbon fiber woven fabrics are broadly used as intermediate base materials for molding carbon fiber reinforced plastics (CFRP). Although CFRP is used for goods for sports and leisure, materials for aircraft, etc. because it is excellent in mechanical properties such as specific strength and specific elastic modulus, cost reduction of intermediate base materials such as woven fabrics is an important subject as well as cost reduction of carbon fiber itself in order to further enlarge the application for CFRP.
Because carbon fiber is fragile and high in stiffness, essentially it is easily woven. Besides, because carbon fiber has a small diameter of a single fiber, that is, a small single fiber diameter, of 5 to 15 .mu.m as compared with that of a usual natural fiber or synthetic fiber and the tensile elongation at break thereof is also small to be in the range of 1.5 to 2.5% and further the knot strength thereof is low, generation of fluffs in a weaving process is inevitable. Namely, it is a difficult fiber to weave From such points, for example, as described in JP-A-SHO 63-315638, it is woven while paying attention to generation of fluffs and yarn cutting, using a shuttle loom or a rapier loom.
In a shuttle loom or a rapier loom, however, the driving speed of wefts is suppressed to a low range of about 80 to 200 picks/min by the weaving mechanism, and there is a problem that the efficiency is reduced.
On the other hand, as a weaving machine capable of performing a high-speed weaving, a water-jet loom, wherein a weft to be flown or picked is placed on water with a high pressure injected from a nozzle (water-jet flow) is known. However, as a result of weaving using such a water-jet loom and using a carbon fiber yarn as the weft, the weaving could be performed with no trouble for a certain period of time, but during weaving, the nozzle may become clogged with fluffs generated on the weft by abrasion between the weft and various guides and miss the weft and therefore, an operator may be forced to stop the machine.
Further, with respect to the warp, warps comprising carbon fiber yarns are abraded violently with healds and reed dents caused by the vertical motion of the healds and the oscillating motion of the reed, and also fluffs are generated. If fluffs are generated, not only the quality of the woven fabric is reduced, but also fluffs sticking on the reed dents and the warps are dispersed in the width direction of the woven fabric by being removed therefrom by the weft and being conveyed together with the weft when the weft is flown, thereby causing a defect of the woven fabric. Furthermore, the warps are easily cut when fluffs are accumulated on the reed dents, and because the accumulated fluffs must be removed every time after the weaving has been performed at a length of about 100 m in order to prevent this problem, there is also a problem that the efficiency is bad.
From the above-described problems, in the manufacture of a carbon fiber woven fabric by the conventional water-jet loom, although the weaving speed is high, the frequency of machine shut down is high, and the efficiency as a whole is not good.